阅读说明：本技术 滤烛 (Filter candle ) 是由 S·海登雷希 W·哈格 于 2021-06-02 设计创作，主要内容包括：本发明涉及滤烛,其用于气态流体,包括：一个或多个过滤元件,其为中空圆柱体的形状,由多孔材料制成,其中多个过滤元件具有大致相同的内直径和外直径并且彼此同轴地直列布置；支撑元件,其包括设置在所述一个或多个过滤元件内的金属管,其中所述金属管的外直径小于过滤元件的内直径,并且其中所述金属管具有壁,所述壁具有多个穿孔；以及至少两个环形密封盘,其外直径等于或大于过滤元件的外直径,并且其内直径小于过滤元件的内直径,其中第一末端密封盘和第二末端密封盘设置在单个过滤元件或直列设置的多个过滤元件的相对轴向端面处,并且其中可选地进一步的内部密封盘设置在多个过滤元件的两个相邻过滤元件之间。(The invention relates to a filter candle for gaseous fluids, comprising: one or more filter elements in the shape of a hollow cylinder made of a porous material, wherein the plurality of filter elements have substantially the same inner and outer diameters and are coaxially arranged in-line with each other; a support element comprising a metal tube disposed within the one or more filter elements, wherein an outer diameter of the metal tube is less than an inner diameter of the filter elements, and wherein the metal tube has a wall with a plurality of perforations; and at least two annular sealing discs having an outer diameter equal to or greater than the outer diameter of the filter element and an inner diameter less than the inner diameter of the filter element, wherein a first end sealing disc and a second end sealing disc are provided at opposite axial end faces of a single filter element or a plurality of filter elements arranged in line, and wherein optionally a further inner sealing disc is provided between two adjacent filter elements of the plurality of filter elements.)

1. A filter candle (10; 50) for gaseous fluids, in particular for hot gas filtration, comprising:

-one or more filter elements (12; 52) in the shape of a hollow cylinder made of a porous material, wherein the plurality of filter elements (12; 52) have substantially the same inner and outer diameter and are coaxially arranged in line with each other;

-a support element (16) comprising a metal tube arranged inside the one or more filter elements (12; 52), wherein the outer diameter of the metal tube (16) is smaller than the inner diameter of the filter elements (12; 52), and wherein the metal tube (16) has a wall (24) with a plurality of perforations (26); and

-at least two annular sealing discs (34, 36; 54) having an outer diameter equal to or larger than the outer diameter of the filter element (12; 52) and an inner diameter smaller than the inner diameter of the filter element (12; 52), wherein a first and a second end sealing disc (34, 36) are arranged at opposite axial end faces of a single filter element (12) or of a plurality of filter elements (52) arranged in line, and wherein optionally a further inner sealing disc (54) is arranged between two adjacent filter elements (52) of the plurality of filter elements (52),

wherein the one or more filter elements (12; 52) and optional internal sealing discs (54) are compressed between the first and second end sealing discs (34, 36).

2. The filter candle (10) according to claim 1, wherein the filter candle (10) comprises only one filter element (12) having an axial length of preferably about 0.5m to about 3.0m, more preferably about 1.0m to about 2.5 m.

3. The filter candle (50) of claim 1 wherein the filter candle (50) comprises a plurality of filter elements (52) arranged in-line, the total axial length of the filter elements preferably being about 0.5m to about 6.0m, preferably about 1.5m to about 5.0 m.

4. The filter candle (50) according to claim 3, wherein the filter candle (50) comprises two to eight filter elements (52), preferably three to five filter elements (52).

5. Filter candle (10; 50) according to any one of claims 1 to 4, wherein the one or more filter elements (12; 52) have an outer diameter of about 30mm to about 150mm, preferably about 60mm to about 70mm, and an inner diameter of about 15mm to about 120mm, preferably about 40mm to about 50 mm.

6. Filter candle (10; 50) according to any one of claims 1 to 5, wherein the radial distance between the filter element (12; 52) and the metal tube is from about 1mm to about 5mm, preferably from about 3mm to about 4 mm.

7. Filter candle (10; 50) according to any one of claims 1 to 6, wherein each sealing disc (34, 36; 54) comprises an annular metal disc (46), preferably a steel disc, and a gasket (48) provided on one or both sides of the metal disc (46) in contact with the filter element (12; 52) for providing a substantially gas-tight seal between the filter element (12; 52) and the sealing disc (34, 36; 54) and allowing radial movement of the filter element (12; 52) relative to the sealing disc (34, 36; 54).

8. The filter candle (10; 50) of claim 7, wherein the gasket (48) comprises graphite, metal fibers, metal mesh, polymeric material, or a combination thereof.

9. Filter candle (10; 50) according to one of claims 1 to 8, wherein one or more of the sealing discs (34, 36; 54), in particular one of the end sealing discs (34, 36) and/or the internal sealing disc (54), comprises an elastic compensation element (56).

10. Filter candle (10; 50) according to any one of claims 1 to 9, wherein the one or more filter elements (12; 52) are made of a ceramic material, preferably a material comprising sintered silicon carbide.

11. Filter candle (10; 50) according to any one of claims 1 to 10, wherein the metal tube (16) is a steel tube, preferably with a wall thickness of about 2mm to about 10mm, in particular about 3mm to about 6 mm.

12. Filter candle (10; 50) according to any one of claims 1 to 11, wherein the axial length of the metal tube (16) is greater than the total axial length of the filter element (12; 52), and wherein the perforations (26) are evenly distributed over an intermediate section (18) of the metal tube (16) extending within the filter element (12; 52).

13. Filter candle (10; 50) according to claim 12, wherein a first end section (20) of the metal tube (16), which preferably comprises an axial discharge opening (30) for gaseous fluid, extends outside the filter element (12; 52) and through the first end sealing disk (34), and wherein the first end sealing disk (34) is fixed to said first end section (20), preferably by welding or screwing.

14. Filter candle (10; 50) according to claim 13, wherein a second end section (22) of the metal tube (16), which is preferably closed at its axial end (32), extends outside the filter element (12; 52) and through the second end sealing disk (36), and wherein the second end sealing disk (36) is axially movable relative to the metal tube (16).

15. Filter candle (10; 50) according to claim 14, wherein the one or more filter elements (12; 52) are compressed between the first and second end sealing discs (34, 36) by an axial force exerted by a spring element (38), preferably a high temperature spring, against the second end sealing disc (22) and a flange element (40) fixed to the second end portion (22) of the metal tube, on the second end sealing disc (36).

16. The filter candle (10; 50) of claim 15 wherein compression of the one or more filter elements (12; 52) is such as to permit radial movement between the filter element (12; 52) and the adjacent sealing disk (34, 36; 54) until the filter element (12; 52) is in contact with the metal tube (16).

Technical Field

The invention relates to a filter candle for gaseous fluids, in particular for hot gas filtration. A typical application of such filter candles is the purification of industrial flue gases or exhaust gases by removal of particles.

Background

The filter candles for hot gas applications according to the prior art are generally based on porous filter elements in the shape of a hollow cylinder with one closed end. The gaseous fluid to be purified passes from the outside through the wall of the filter element, generally in a substantially radial direction, and leaves the filter element through an axial opening. A plurality of such filter candles may be arranged parallel to one another to form a filter assembly.

This type of filter candle can also be used as a blowback filter, wherein the filter element is cleaned by a high pressure air stream flowing in the opposite direction to the normal filtration process.

The filter candles are typically made of ceramic materials, and are rigid and self-supporting. However, one major drawback is their limited mechanical strength, in particular their limited tensile and bending strength. Thus, if the filter candles are subjected to mechanical stress, there is a risk of failure, which may be the case, for example, when dust bridges occur between the filter candles.

Disclosure of Invention

It is an object of the present invention to provide a filter candle with improved mechanical strength.

This problem is solved by a filter candle according to claim 1.

In the filter candle of the present invention, the support element is disposed within one or more cylindrical filter elements. The support element comprises a metal tube which itself has a much higher tensile and bending strength than the porous material of the filter element. After passing through the filter element, the gaseous fluid enters the metal tube through a plurality of perforations and exits the filter candle through an opening at one end of the tube.

In order to provide an unimpeded flow through the entire inner surface area of the filter element or elements, an annular gap is present between the inner surface and the outer surface of the metal tube. If a force is exerted on the filter element in the radial direction, the filter element will move and/or bend until it abuts against the metal tube. In this way, the metal tube supports and stabilizes the filter element and increases the mechanical strength of the entire filter candle, in particular its bending strength.

In accordance with the present invention, one or more filter elements are compressed between the first and second end sealing discs using the relatively high compressive strength of the porous material of the filter element. However, compression of the filter element allows radial movement between the filter element and the adjacent end sealing disk until the filter element contacts the metal tube, as described above. During this movement, the axial end faces of the filter element must be covered tightly by the sealing discs.

According to a first preferred embodiment of the invention, the filter candle comprises only one filter element. In this case, only two sealing discs are provided on both axial end faces of the filter element. The filter element preferably has an axial length of about 0.5m to about 3.0m, more preferably about 1.0m to about 2.5 m.

According to a second preferred embodiment of the invention, the filter candle comprises a plurality of filter elements arranged in line. In this case, in addition to the two end sealing discs, further internal sealing discs are provided between adjacent filter elements. This segmentation of the filter candle provides further flexibility and resiliency against mechanical stresses, in particular against radial forces applied to the filter candle.

The total axial length of the plurality of filter elements of the second embodiment may be within the same preferred range as the length of the single filter element of the first embodiment. However, segmentation is particularly preferred for larger lengths, for example from about 1.5m to about 5.0 m. In the second embodiment, the filter candle preferably comprises two to eight filter elements, more preferably three to five filter elements. The filter elements may have the same or different lengths.

The one or more filter elements preferably have an outer diameter of about 30mm to about 150mm, more preferably about 60mm to about 70mm, and an inner diameter of about 15mm to about 120mm, more preferably about 40mm to about 50 mm. The wall thickness of the hollow cylinder is typically in the range of about 7.5mm to about 20 mm.

The radial distance between the filter element and the metal tube is preferably from about 1mm to about 5mm, more preferably from about 3mm to about 4 mm. The outer diameter of the annular seal disk is equal to or larger than the outer diameter of the filter element, and the inner diameter of the seal disk is smaller than the inner diameter of the filter element, so that the axial end face of the filter element can be brought into full contact with the seal disk even if the filter element abuts against the metal pipe.

In the present invention, it is preferable that each seal disk comprises: an annular metal disc, preferably a steel disc; and a gasket disposed on one or both sides of the metal disc in contact with the filter element; that is, the end seal disk is provided with a gasket on one side and the inner seal disk is provided with a gasket on both sides. In this manner, a substantially airtight seal between the filter element and the sealing disk is provided, while allowing radial movement of the filter element relative to the sealing disk.

Preferably, the gasket for the sealing disk of the candle of the present invention comprises graphite, metal fibers, metal mesh, polymeric material, or combinations thereof. These and other suitable gasket materials are known in the art. The choice of a particular gasket material will also depend on the intended use of the filter candle of the present invention and the corresponding operating conditions. For example, most polymeric gasket materials are limited in their operating temperature.

The thickness of the gasket for sealing the disk is preferably from about 1mm to about 5mm, preferably from about 1.5mm to about 3 mm.

One or more of the sealing discs may include a resilient compensation element. In particular, it is preferred if one of the end sealing discs comprises an elastic compensation element. In embodiments of the invention having more than one filter element, it is also preferred that the internal sealing disk comprises an elastic compensation element. Thereby, an axial bending of two adjacent filter elements relative to each other can be achieved. The inner sealing disk may comprise such a compensating element in addition to or instead of the annular metal disk.

The filter element or elements of the filter candle of the present invention are typically made of a ceramic material, preferably a material comprising sintered silicon carbide. These ceramic materials having a high porosity are known in the prior art. Furthermore, the filter element may comprise one or more catalytic materials, in particular catalytic materials for removing nitrogen oxides.

The metal tube used as the support element of the filter candle of the present invention is preferably a steel tube, more preferably having a wall thickness of from about 2mm to about 10mm, especially from about 3mm to about 6 mm. However, in certain cases it may also be preferable to use other metals or alloys, for example in cases where the gaseous fluid to be filtered requires a support element with higher corrosion or chemical resistance. This applies correspondingly to the annular metal disk which seals the disk.

Typically, the axial length of the metal tube is greater than the total axial length of the filter element, wherein an intermediate section of the metal tube extends within the filter element and two end sections of the metal tube extend to the outside of the filter element. In this case, the perforations in the metal tube wall are distributed uniformly over the middle section, wherein the walls of the two end sections are free of perforations.

The number and size of the perforations are preferably selected such that the total area of the perforations is large enough to promote radial flow of the gaseous fluid into the metal tube, but small enough to maintain sufficient mechanical stability of the metal tube. With regard to the latter requirements, the wall thickness of the metal tube must also be taken into account.

According to a preferred embodiment of the invention, the first end section of the metal tube extends outside the filter element and through the first end sealing disk, wherein the first end sealing disk is fixed to said first end section, preferably by welding or screwing. It is further preferred that the first end section comprises an axial discharge opening for the gaseous fluid.

In the above embodiment, the second end section of the metal tube may also extend outside the filter element and through the second end sealing disk, wherein the second end sealing disk is axially movable relative to the metal tube. It is further preferred that the second end section is closed at its axial end, allowing gaseous fluid to be discharged only through the first end section.

By providing a first end sealing disk fixed to the metal tube and a second end sealing disk movable relative to the metal tube, differences in thermal expansion of the porous material of the metal tube and the filter element are taken into account.

Preferably, the one or more filter elements are compressed between the first and second end sealing discs by an axial force exerted on the second end sealing disc by a spring element, preferably a high temperature spring, abutting the second end sealing disc and a flange element fixed to the second end portion of the metal tube.

Since the metal tube is preferably closed at the second end section, as described above, and the gaseous fluid is only discharged through the first end section, a spring cover may preferably be provided to enclose the second end section comprising the spring element, thereby protecting the spring element from dust or the like from the outside. The spring cap preferably seals against the second end seal disk.

A plurality of filter candles of the present invention may preferably be arranged parallel to one another to form a filter assembly, in particular for hot gas filtration.

The invention also relates to the use of a filter candle according to the invention or of a filter assembly comprising a plurality of filter candles according to the invention for hot gas filtration, in particular for purifying industrial flue gases or exhaust gases.

Drawings

The exemplary embodiments described below serve to explain the invention in further detail with reference to the figures, in which

FIG. 1 shows a longitudinal cross-sectional view of a first exemplary embodiment of a filter candle of the present invention; and

fig. 2 shows a longitudinal sectional view of a second exemplary embodiment of a filter candle of the present invention.

Detailed Description

In fig. 1, a first exemplary embodiment of a filter candle 10 according to the invention is shown in a longitudinal sectional view. The illustration of the filter candle 10 is schematic and not necessarily drawn to scale.

In this first embodiment, the filter candle 10 includes a filter element 12 in the shape of a hollow cylinder. For example, the filter element 12 may have a length of 1.5m, an outer diameter of 60mm and an inner diameter of 40 mm. The filter element 12 is made of a porous material, typically a porous ceramic material. For example, porous filter elements of sintered silicon carbide material, also known as filter candles, are sold by the applicant under the trade mark "Dia-schumalitith".

Inside the filter element 12, a metal tube 16 (typically a steel tube) is provided as a support element extending coaxially with the filter element along the rotation axis 14. The metal tube 16 includes an intermediate section 18 extending within the filter element 12, and first and second end sections 20 and 22 extending outside the filter element 12. The wall 24 of the metal tube 16 has a plurality of perforations 26 evenly distributed over the middle section 18 of the metal tube 16, while the wall 24 in the first and second end sections 20 and 22 is not perforated.

The metal tube 16 may have an outer diameter of, for example, about 34mm, with a wall 24 having a thickness of 4 mm. In any event, the outer diameter of the metal tube 16 is less than the inner diameter of the filter element 12 such that an annular gap 28 is formed between the filter element 12 and the metal tube 16. The gap 28 may have a width of, for example, about 3 mm.

In a typical application of the filter candle 10, for example for hot gas filtration, the gaseous fluid to be filtered is passed from the outside in a generally radial direction through the filter element 12 into the annular gap 28 and is inserted through the perforations 26 into the metal tube 16. The gaseous fluid then exits the metal tube 16 through an axial discharge opening 30 at the first end section 20, while the second end section 22 is closed at its axial end 32.

Filter candle 10 further includes two annular sealing discs, first end sealing disc 34 and second end sealing disc 36. First end seal disk 34 surrounds and is secured to first end section 20 of metal tube 16 by welding, as indicated at 37, to provide a gas-tight closure of annular gap 28 at first end section 20, rather, second end seal ring 36 surrounding second end section 22 of metal tube 16 is axially movable relative to metal tube 16 to allow for differential thermal extension of metal tube 16 and filter element 12.

Filter element 12 is compressed between first and second end seal rings 34 and 36 with a compressive force applied by spring element 38, which is preferably a high temperature spring. The spring element 38 surrounds the second end section 22 of the metal tube 16 and abuts the second end sealing disk 36 and a flange element 40 which is fixed to the second end section 22, for example by a nut 42.

The second end section 22 of the metal tube 16 including the spring element 38 is covered by a spring cap 44 which abuts the second end sealing disk 36. Spring cover 44 protects spring element 38 from dust and the like from the outside, and it also inhibits gaseous fluids that may pass through the small annular gap between metal tube 16 and second end sealing disk 36.

Each of end sealing disks 34 and 36 includes a metal disk 46 (typically a steel disk) and a washer 48. The gasket is in direct contact with a corresponding axial end face of the filter element 12 to provide an airtight seal, but at the same time allow radial movement of the filter element 12. First end sealing disk 34 may additionally include a resilient compensation element.

Due to external forces acting on the filter element 12, the filter element 12 will move radially along the gasket until the filter element comes into contact with the metal tube 16. At this point, the metal tube 16 supports and stabilizes the filter element 12, ideally preventing further bending and fracture of the filter element 12. The metal tube 16 thus acts as a support element that increases the overall tensile and bending strength of the filter candle 10.

To provide a gas-tight seal at the end face of the filter element 12 at each location, the outer diameter of the annular sealing discs 34 and 36 is greater than or equal to the outer diameter of the filter element 12, and the inner diameter of the sealing discs 34 and 36 is less than the inner diameter of the filter element 12. Specifically, the difference between the outer and inner diameters of sealing discs 34 and 36 should be at least twice the radial distance between filter element 12 and metal tube 16.

In fig. 2, a second exemplary embodiment of a filter candle 50 of the present invention is shown in a longitudinal sectional view. The filter candle 50 of the second embodiment corresponds to the filter candle 10 of the first embodiment, except for the different points described below. Identical or corresponding elements in the first and second embodiments have the same reference numerals.

The second embodiment of filter candle 50 includes a plurality of shorter porous material filter elements 52 rather than a single filter element. In this example, four filter elements 52 are shown, but a lesser or greater number of filter elements is also possible. Each filter element 52 is shaped as a hollow cylinder having the same inner and outer diameters, coaxially arranged in-line along the axis of rotation 14 of filter candle 50.

The individual filter elements 52 may be the same or different in length, and may have an overall length that is the same as the length of the individual filter elements of the first embodiment (e.g., 1.5 m). However, the use of a plurality of filter elements 52 is also particularly advantageous for larger overall lengths, for example up to 6 m.

Between each two adjacent filter elements 52, an internal annular sealing disc 54 is provided. Filter element 52 is compressed between first and second end sealing discs 36 and 38 along with inner sealing disc 45 as in the first embodiment of filter candle 10.

The segmentation into multiple filter elements 52 provides further flexibility and resiliency of filter candle 50 to resist mechanical stresses, particularly radial forces exerted on filter candle 50. To this end, the internal sealing disc 54 generally comprises an elastic compensation element 56 which allows two adjacent filter elements 52 to bend axially relative to each other. The elastic compensation element 56 is provided with washers 58 on both sides.

Measurement of bending Strength

The bending strength of the inventive filter candle according to the first exemplary embodiment was determined in a 4-point bending test. The filter element of the filter candle tested was a hollow cylinder of ceramic material based on sintered silicon carbide (Dia-Schumalitith) having a length of 1.5m, an outer diameter of 60mm and an inner diameter of 40 mm.

In the 4-point bend test, the filter element of the filter candle of the present invention broke under a force of about 4,800N.

The corresponding filter elements conventionally used as filter candles, alone, without a supporting metal tube, typically break under bending forces in the range of 2,500 to 3,500N.

Thus, the flexural strength of the filter candle of the present invention is increased by about 60% compared to a corresponding conventional filter candle.